Telephone receiver



May 31, 1932. w. G. SHULL TELEPHONE RECEIVER Filed Nov. 14, 1927 2Sheets-Sheet 1 Imm- DJiuiam E. Ehull @M May 31, 1932. w. G. SHULLTELEPHONE RECEIVER Filed Nov. 14. 1927 2 Sheets-Sheet 2 Inuen ur-- imamET. Shun WW?- Patented May 31, 1932 UNITED STATES PATENT .FFICE WILLIAMG. SHULL, OF CHICAGO, ILLINOIS, ASSIGNOR, BY MESNE ASSIGNMENTS, T

ASSOCIATED ELECTRIC LABORATORIES, INCL, O1 CHICAGO, ILLINOIS, A CORPORA-TION OF DELAWARE TELEPHONE RECEIVER Application filed November 14, 1927.

My invention relates to telephone receivers and particularly to the typetermed loud speakers.

One object of my invention is the design of an instrument which will besubstantial and cheap to manufacture and one which will not requirefurther adjustment after it has been properly assembled.

In the present instance, I have shown the speaker provided with a conereproducer. The cone is connected to a reed which is anchored or firmlyfastened at both ends. The connection from the cone is made to thecentral portion of the reed. A portion of the reed lies between the polepieces of two per manent horse-shoe magnets and the central portion ofthe reed is encircled by two operating coils which are responsive tovoice or similar currents causing the vibration of the reed. Theoperation of the reed in turn operates the cone which reproduces ormagnifies the vibrations of the reed.

My invention is illustrated in the accompanying drawings, wherein:

Fig. 1 is a rear view of the loud speaker with the cover removed to showthe arrangement of the operating parts.

Fig. 2 is a top view of Fig. 1 with the cone and felt ring shown insection.

Fig. 8 is a plan view of one of the operating coils showing the reedpassing through the opening therein.

Fig. 4c shows the construction of the reed.

Referring to Figs. 1 and 2 it will be noted the cone and magneticstructure for operating it are mounted upon a base 50.

The support for the outer edge of the cone 1 consists of an upright 5attached to the base by the two brackets 51 and 52 as shown. The support5 is provided with a circular opening which is lined with a wide butlightweight felt washer or cushion 2 provided with the two rims orbinders 4t and 6 also of felt. The rim 4 is glued to the inner surfaceof the opening in the upright 5.

The outer edge of the cone 1 which is preferably made of parchment issupported or imbedded in the cushion 2 as shown in Fig. 2.

The apex of the cone is provided with a threaded rod or pin 7 which isadjustably Serial No. 232,97fi.

held in place by the two nuts 8 and 9. The rod 7 is also attached to thereed 10 as shown in Fig. 2.

The magnetic structure for operating the cone 1 is mounted upon twoangle supports 31 and by means of the screws 21 and 13 which are ofsuificient length to extend through the nuts 22 and 14 and pass throughclearance holes in the supports 31 and 82 which are then clamped to themagnetic structure by the nuts and 61. The angle supports are in turnfastened to the base 50 by screws 3834 and nuts 3935.

The two permanent horseshoe magnets 23 and 24, the reed 10 and operatingcoils 410 and 41 are mounted between the two brass plates 11 and 12. Themagnet 23 is provided with two L-shaped soft iron pole pieces 30 and 37,while the magnet 2a is likewise provided with two similar pole pieces 29and 36. The poles of the magnets 23 are provided with clearance holesfor the iron screws 25 and 28 which respectively engage the threadedopening in the pole pieces 37 and 30, thus firmly attaching the magnetand its pole pieces to the plate 12. The magnet 2% and its pole piecesare likewise firmly attached to the plate 11 by means of two screws 27and 26.

The two coils l0 and 41 are each attached to a brass frame. As shown inFig. 3, the frame 46 is provided with turned-over cars which grip thecoil and hold it firmly clamped in place. The cars or extensions 71 restupon the plates 11 and 12 as shown in Fig. 2. Each coil is provided witha rectangular opening 49 through which the reed 10 passes. The openingis of sufficient size to allow the reed to vibrate freely.

Each end of tl e reed 10 is provided with clearance holes 68 and 69through which the screws 18 and 21 pass. One end of the reed is clampedbetween two spacing collars 15 and 16, while the opposite end is clampedbetween spacing collars 19 and 20. The two screws 18 and 21 pass throughthe two plates 11 and 12 and also through the openings in the reed 10.and by tightening the nuts 14; and 22 the entire structure is firmlyclamped together, forming a single unit.

The two frames 46 and 47, holding the coils 40 and 41 respectively, areadjusted and held in place by the set screws 4243 and 44-45 which passthrough the plates 11 and 12 as shown in Fig. 2. By means of thesescrews the coils can be so adjusted that the reed 10 is centrallylocated within the opening 49. For additional adjustment or alignmentthe shims 17 and 18 may be provided for positioning the reed 10 inrelation to the pole pieces 30, 37, 29 and 36.

The pin 7 which connects the cone 1 to the reed 10 passes through anopening in the plate 11 and the space between the plates 46 and 47 whichsupport the coils 40 and 41.

A terminal strip 53 of insulating material carrying the two clips 55 and56 is fastened to the plate 12 by means of a screw 54. The windings ofthe coils 40 and 41 are connected to the clips which are in turnconnected to a two-conductor cord 57. This cord may be connected to aradio receiving set or other device. The current received from such adevice passes through the coils 40 and 41 and exerts a push-pull effectupon the reed 10 which in turn operates the cone 1 causing the sounds tobe magnified or reproduced.

From the foregoing it will be noted that the apex of the cone 1 issupported by the rod 7 fastened to the reed 10 while the outer edge ofthe cone is supported or cushioned by the ring of felt.

The reed 10 has a central magnetic portion 63 of iron while the two endportions 62 and 64 are of non-magnetic material such as phosphor bronze.The three portions are joined by the sets of tongues and grooves 65 and66 as shown in Fig. 4.

The joints are soldered to form a stiff and substantially a one-piecereed. As shown in Fig. 2 the tongues and grooves extend beyond the coils40 and 41 far enough for the central magnetic portion 63 to be actedupon by the short portions of the pole pieces 36-37 and 29-30. Thisprevents the magnetic portion of the reed from being influenced by straymagnetic currents flowing across the poles of the magnets 23 and 24.

The end portions of the reed being of nonmagnetic material are notaflected by such current and consequently a clear free action of thereed takes place caused by currents acting upon its central portion.

By having the outer edge of the cone resting freely within the separatering of yielding material allows the cone and magnetic structure toalways remain in proper relationship or adjustment.

Any variation due to expansion or contraction is automatically taken up,as the edge of the cone is free to move and assume any position of restwithin the supporting ring, as its edge is but slightly imbedded in thering and in practice just enough to allow proper support and movement.

If the outer edge of the cone was rigidly fastened to the support, thenany lack of proper adjustment will create a strain on one port-ion ofthe cone, causing distortion or lack of clearness in the reproducedsounds.

What is claimed is:

1. In an acoustic device, a frame havlng a fiat circular inner surface,a resilient lining secured to the inner surface of the frame solelythrough the medium of the surface on its outer circumference, and a coneshaped diaphragm frictionally supported by and freely movable with saidlining.

2. In an acoustic device, a frame having a flat circular inner surface,a resilient lining secured to the inner surface of the frame solelythrough the medium of the surface on its outer circumference, and a conethe diameter of the base of which is slightly greater than the openinremaining in said frame after the lining is in place, said cone beinginserted and held in place in the opening solely by slight compressionof said resilient material against the outer periphery of the base ofsaid cone.

3. In an acoustic device, a cone shaped diaphragm, a frame member havinga cylindrical opening therein the diameter of which 18 at least twentypercent greater than that of the base of the cone, and a resilientsubstance secured to said frame and frictionally holding said cone inplace within the opening.

4. In an acoustic device, a diaphragm, and means for supporting saiddiaphragm at its outer extremity, comprising, a frame lined withresilient material against which the diaphragm is held by slightlycompressing the said resilient material between the outer extremity ofthe diaphragm and the inner extremity of said frame, the front and rearsurfaces of said lining lying in parallel planes at right angles to theinner and outer surfaces of said lining, and being left free to movewith the diaphragm an extent depending solely on the resiliency of thesaid lining.

In witness whereof, I hereunto subscribe my name this 9th day ofNovember, A. D.

WILLIAM G. SHULL.

